Final answer:
Chemistry principles dictate that the correct significant figures must be used when adding or subtracting measurements, and the molar mass or empirical formula is key in determining specific masses of compounds based on quantifiable moles.
Step-by-step explanation:
When measurements are combined through addition or subtraction, the result should be rounded to the least precise decimal place of the components. For example, when you add 16.7 g and 5.24 g, the hundredths place of the first measurement (16.7) is unknown, so the correct sum should be rounded to the tenths place as 21.9 g. Similarly, the molar mass of a compound can be calculated from its molecular or empirical formula, and individual masses of these compounds can be derived from the total molar mass and number of moles present.
Significant figures are crucial in reporting measured values and calculated results in chemistry to accurately represent the certainty of the measurements and computations involved.